I was cleaning my windows registry today and by mistake some of the Keys,values,data in a rush. Now some of the programs aren't working and when I right click on icons and folders,some of the options aren't there like 'scan this file','extract it',etc. Can I somehow restore the registry to default by which all the keys and values,data will be restore?

Solid_Snake4RD, What program were you using to clean the registry? Did it make a backup? Try a System Restore to the closest date prior to when you cleaned the registry. If you're not familiar with the registry leave it alone and DON'T use any so called registry cleaner as they do more harm than good. Start>Programs>Accessories>System Tools>System Restore. Tufenuf

I was cleaning ti manually cause I was haveing problem reinstall Nero 9 and mistakenly i deleted one or two thing as i pressed delete button twice more than required so it deleted thing other than which I wanted to delete System restaore is bot an option cause i just reinstalled my system and there are no restore points

Without a System Restore point you are up the creek. Try a repair install or reinstall the system.